The present invention relates to an automatic loader used for loading and unloading samples into a resistance furnace, for moving samples for analysis into and out of a high temperature furnace while protecting the sample from contamination by ambient atmosphere.
A common method of analyzing the content of a sample is to place the sample in a furnace at a sufficient temperature that gases are driven from the sample. The gases are then analyzed to obtain the desired information. Any ash or other residue then remaining from the sample is discarded. Such furnaces can be used to analyze any gas which can be obtained by burning or exposing a sample in a furnace to high temperature to obtain information such as carbon or sulfur content of a sample.
A conventional furnace to perform such analysis may be a resistance furnace having an elongated central tube in which the sample is positioned at the tube midpoint. The interior of the tube is flooded with a gas such as oxygen to isolate the sample from the atmosphere and to standardize the interaction with the sample. The mid point is the point of highest temperature, and thus the point where the gasses are driven or burned from the sample. The gasses to be analyzed are then drawn from one end of the furnace. The sample is normally in a crucible or boat which is placed in and removed from the furnace by hand through the same opening in the furnace. A number of attempts have been made to automate the process of introducing the sample into a furnace, drawing out of the gasses for analyzes and, thereafter, removing the remaining ashes and the crucible which carried the sample. For example, U.S. Pat. No. 5,314,662 to Hemzy, et al., and U.S. Pat. No. 5,395,586 to Hemzy, et al., show systems for automatically pushing into the furnace and retrieving a sample in a crucible from the same end of the furnace.